HIGH-INCIDENCE OF MONOCLONAL PROTEINS IN THE SERUM AND URINE OF CHRONIC LYMPHOCYTIC-LEUKEMIA PATIENTS

Abstract

Chronic lymphocytic leukemia (CLL) is generally considered a nonsecretory B cell immunoproliferative disorder. Conventional electrophoretic and immunoelectrophoretic methods have revealed serum monoclonal proteins in < 10% of these patients. However, there is increasing experimental evidence from in vitro studies demonstrating that CLL cells may secrete ig, particularly free l. chains. The serum and urine of 36 consecutive CLL patients was examined for monoclonal proteins using sensitive immunochemical methods (high resolution agarose gel electrophoresis combined with immunofixation). The results obtained were correlated with the Rai stage, quantitative Ig levels and lymphocyte membrane Ig phenotype of the leukemic cells. Twenty-three monoclonal proteins were identified in the serum or urine of 22 patients, an incidence of 61%. Six patients had serum monoclonal proteins, 7 had only urinary monoclonal proteins and 9 had monoclonal proteins in serum and urine. In every instance the monoclonal protein was the same l. chain type as expressed on the leukemic cells. The monoclonal proteins observed in the serum or urine of CLL patients are probably secretory products of the tumor cell, their discovery is probably a function of the sensitivity of the method used for their detection.